Lemon and Mandarin Tiramisu
Drain mandarins and mix 4 tablespoons juice with agar. Rinse 1 lemon in hot water, pat dry, zest and juice. Stir lemon juice into mandarin juice mixture in a saucepan and heat gently for about 2 minutes. Refrigerate juice mixture until it begins to set. Mix quark, sugar and mascarpone, stir into juice mixture and refrigerate.
Juice remaining lemon and mix with vanilla sugar and rum. Briefly soak ladyfingers in lemon juice mixture. To assemble tiramisu, layer ladyfingers, quark mixture and mandarins into a shallow baking dish, finishing with mandarins on top. Refrigerate tiramisu for 2-3 hours. Garnish tiramisu with mint leaves as desired to serve.